Reciprocative electromagnetic tool



y 3, 1952 H. D. ANDREAE ET AL RECIPROCATIVE ELECTROMAGNETIC TOOL 3 Sheets-Sheet 1 Filed Sept. 17, 1947 FIG.|.

INVENTORS HOBART DANDREAE MAYNARD RANDREAE WAYNE A.ANDREAE and fi ATTORNEY July 8, 1952 H. D. ANDREAE ET AL 2,602,475

RECIPROCATIVE ELECTROMAGNETIC TOOL.

3 Sheets-Sheet 2 Filed Sept. 17, 1947 I N VEN TORS ATTORNEY July 8, 1952 H- D. ANDREAE ET AL RECIPROCATIVE ELECTROMAGNETIC TOOL 3 Sheets-Sheet 5 Filed Sept. 17, 1947 FIGJO.

INVENTORS HOBART D. AN DREAE TT T- MAYNARD R.ANDREAE WAYNE A. ANDREAE FIG.9.

Patented July 8, 1952 -UNITED1 IS'TATE RECIPROCATIVE ELECTROMAGNETIC TOOL Hobart D. Andreae, Maynard Wayne A. Andreae, Birmingham,

Andreae, and

Mich.

- Application September 17, 1941, Serial No. 774,488

This invention relates to reciprocative electromagnetic tools, and particularly electromagnetic jig saws. The invention may be considered an improvement on the disclosure of the Young Patent 1,948,229 issued February20, 1934. i An object of the invention is to adapt a tooldriving armature to flex to and from an electromagnet and to provide for bodily adjusting such magnet to and from the armature to. regulate the air gap of the magnetic field.

Another object is to associate a tool-driving armature with an electromagnet, to interpose a resilient spacer means between the magnet and a support therefor, and to securethe magnet to the support by a connection applying a regulable stress to the spacer means. i

Another object is to interpose a corrugated sheet metal spring between anelectromagnet and a support therefor, and toclamp the magnet to the support by an element extending through and imposing compression on the spring.

Another object is to support an electromagnet 6. Claims. (01. 143-43) upon and within an open-topped housing, to 1 provide said housing with a cover serving also as a work table, to dispose a flexiblearmature beneath said cover, for vibratory actuation bythe magnet, and to operatively position the armature by securing its ends between the cover and housi Another object i to mount the ends of a vibratory flexible armature in cushions of rubber or the like set into holders suited to be rigidly clampedintheir positions of use, 1 Another object is to equip the gooseneck of a jig saw with a guide for the saw blade, adjustable to and from the work table to engage the blade in a desired close proximity to the work. These and various other objects are attained by the construction hereinafter described and .illustrated in the accompanying drawings, wherein:

Fig.1 is a side elevational view of our invention as incorporated in an electromagnetic, jig saw.

Fig. 2 is a, front view of the same. I

Fig. 3 is a longitudinal sectional elevation taken on the line 3-3 of Fig. 2. v

Fig; 4 is a vertical cross sectional view'taken on I the line 4-4 of Fig. l; v

Fig. 5 is a horizontal cross section taken on the line 5--5 of Fig. 4.

Fig. 6 is a perspective view of a spring employed to seat the electromagnet on a support.

Fig.7 is a perspective view of one of a pair of cushioning mountings for the armature extremi ties.

ble. Said studs are threaded into posts .ends'are free to recede from Fig.-8'is a perspective view 3a modification of the construction illustrated Figs. 1-8. 1

Fig. 10 is a horizontal sectional view of the modification, taken on the line lll-ID of Fig. 9.

In these views, the reference character I designates an approximately rectangular housing, open at top and bottom and formed preferably as a, casting. Centrally disposed in said housing is an electromagnet comprising a coil 2 wound on the center pole piece 3 of a laminated E-shaped Said pole piece and the lateral'pole' pieces 5 and 6 project upwardly from the yoke core 4.

portion of the core and terminate in pole faces 'I preferably slightly below the top edge of the hous ing l.

against the strut. Between the magnet and strut is interposed a corrugated sheet metal spring I l;

substantially equal in width to the core; such spring seating at its extremities i la and mid portion' I lb on the strut, and having crests Hc between its mid portion and ends to seat the 'core. The stud 9 extends through a central aperture I! in said spring, and upon tightening the nut ill, the spring is selectively compressed. It is evident from preceding description that thespring portion as compression is applied, the crests Hc sliding on the bottom face of the core 4 and the extremities I la sliding on the strut, any rotation of'either the spring or magnet being prevented by the marginal upstanding flanges 13 :of the strut.

Surmounting and covering skirt [5 and an annular downwardly site ends of and adjacent the top edge of the housing. The top portions of said end walls and said bosses thereon are outwardly offset, as indicated at I9, rendering the bolts l1 readily accessil8 of the of a hanger adapted to be carried by the gooseneck and to accurately A support for the described electromagnet is formed by a channel-shaped strut 8 integrally downwardly through its anchored center I the housing 1 is a work table l4 having a reinforcing marginal projecting I flange 16, inwardly spaced from said skirt and the hanger table formed interiorly integral with opposite ends of the flange l6.

Coextensive in height with the housing I are two similar pairs of ribs [9a, the ribs of the respective pairs inwardly projecting from the respective end walls of the housing and being equally laterally spaced from the bolts ll. Two similar pairs of ribs 20 on the table, coextensive in height with the flange l6, project inwardly from the ends of such flange. Clamped between the upper and lower jaws formed by the ribs 20 and 19 are elongated metallic receivers 2| hav-- ing lugs 22 at their ends toengage said jaws. Within said receivers are fitted cushions 23 of rubber or like resilient material, medially formed with pockets snugly receiving the ends of a resilient flexible armature 24 of sheet steel or other magnetically active material. of said armature is disposed above the electromagnet for periodic attraction to the pole faces I. Whenthe coil 2 is energizedby an alternating current, the rapid periodic changes in value of such current produce a vibrationof the armature,

its mid portion alternately being attracted to and springing away from the magnet. Mounting of the armature by inserting its ends in cushionsof yielding material, as above described, affords a very essential freedom of movement to said ends, allowing them to tilt and also to move slightly to. and from each other, under, flexure. It is to befnoted that the bolts H are at opposite ends of and inthe medial longitudinal plane of the armature, being thus adapted to draw the upper clamping jaws firmly down upon the end lugs of the receivers 2| to firmly clamp the latter against the lower jaws.

Centrally secured to the armature is an arched bracket25 serving as an anchorage for the lower end'of a saw blade 26, extending freely upward through a central aperture 21 in the table [4. They upper end of said blade is anchored to the free end of a spring arm 28 fixed at its other end on the gooseneck29. The latter is of the usual U -shape, its lower end being fastened by screws 30 to and beneath the table l4 and itsupper end portion being spaced above the table. The top armof the gooseneck projects slightly beyond the blade-mounting end of the spring arm 28 and has adownturnedend 3| to which is clamped, by a bolt 32 and wingnut 32a, a downwardly projectinghanger 33, longitudinallyslotted at 34 to permit its up-and-down adjustment. on thebolt. The upper portion of said hanger is received in anopening 35.of. the gooseneck, to resist any tendencytoturn. about the bolt 32. Thelower portion of the hanger 33 extends rearwardly at adownward inclination across the path of reciprocation of the blade, then i a screw 36, rearwardly of the blade, and terminates in afoot 37 forwardly projecting acrossthe path of the blade and notched to accommodate the blade. The rearwardly inclined portion of downwardly to mount grooved to receive, and guide. the blade.

thrust and the vertical adjustability. of, thev hanger permits its lower end to be maintained in close proximity to work, thicknessof the latter.

despite variations in.

' erative position.

The mid portion is, slotted at 33 to accommodate the blade, and the screw 36 has its headdiametrically }e5.. For most eflicient cutting, with a. minimum;

adjusted while th As compared to earlier types of electromagnetic jig saws, the described construction lends itself to a much quicker and easier assembly. The tightening of a single nut III on the bolt 9, serves to properly position the electromagnet and no flexing of the armature or any supports for same is necessary to insert the armature ends in their cushioning mountings. Employment of only, two boltsv to'secure the work table, to the housing saves further time, as does also'the use of these fastenings to hold the armature in op- The most eflicient operating relation between thearmature and magnet may be readily established since the nut ated.

It. is to be notedthat the hanger 33 adds materially to safety of the described tool, in addition to performing the functions heretofore mentioned. Thus said hanger extends in front of the major portion of such length of theblade' as is exposed yond thetoothed edge of the blade.

In the-modification illustrated by Figs. and

10, the housing 39, table-d0, electromagnet coil 4| and electromagnet core 42 substantially conto secure the table 50 and are headed to seat on receive the bolts; As compared to the first-described construction this a work. table having an-aperture to accommodate accommodatesuch element, and-havingjtslowerend formed with a workengaging foot forwardly pro ectmg across. said path and aperturedto ac:- ,commodate said element and means for the receivers. Itv is preferred,

modificationachieves an increased strengththrough reducing the.

clampsv 5 ing said guide arm to the gooseneck in selectively spaced relations to the table.

2. In a reciprocative tool as set forth in claim 1, a headed screw fixed in the guide arm, and having its head grooved to receive and guide said element.

3. In a reciprocative tool, the combination with a work table having an aperture to accommodate a work-performing element and having a portion forward of said aperture for feeding work to said element, and means for reciprocating such element transversely to the table, of a support spaced above the table, and a guide arm for said element mounted on and depending from the support, forwardly of the path of said element, said arm having a Work-engaging foot at its lower end and having a portion, spaced above such foot, ofiset rearwardly across said path.

4. A reciprocative tool as set forth in claim 3, said foot projecting forwardly across th path of said element.

5. In combination with an electromagnet and a coacting vibratory armature formed of sheet material, of a pair of units for operatively mounting the ends of the armature, each such unit comprising an elongated cushion formed with a socket to receive the corresponding end, and a substantially rigid receiver for said cushion, having lugs extending from the cushion ends for receiving clamping pressure, whereby said cushion affords an angular play of the armature end, a mounting for said electromagnet and units, and means for applying clamping pressure to said lugs.

6. A reciprocative electromagnetic tool comprising an open-topped housing, a work table covering the housing, an electromagnet carried by and within the housing, a resilient vibratory armature extending above and flexible to and from said magnet and having its ends interposed between the housing and work table, resilient cushions engaging and mounting the ends of the armature, metal receivers socketed to retain said cushions, a work-performing element attached to and driven by the armature, and means for securing the work table to the housing, effective through said table to clamp said receivers upon and within the housing.

HOBART D. ANDREAE.

MAYNARD R. ANDREAE.

VJAYNE A. ANDREAE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 39,164 Niederkornet a1. July 7, 1863 228,130 Sutton Mar. 30, 1880 1,234,763 Hills July 31, 1917 1,601,123 King Sept. 28, 1926 1,846,326 Flint Feb. 23, 1932 1,948,452 Young Feb. 20, 1934 2,002,871 Sharp May 28, 1935 2,193,978 Miller Mar. 19, 1940 2,204,233 Schug June 11, 1940 2,243,565 Kimball May 27, 1941 2,243,660 Thompson May 2'7, 1941 2,317,501 Tyler Apr. 27, 1943 2,471,796 Thiberg May 31, 1949 FOREIGN PATENTS Number Country Date 108,981 Switzerland Feb. 16, 1925 

